PLT-3077 Add group messaging (#5489)

* Implement server changes for group messaging

* Majority of client-side implementation

* Some server updates

* Added new React multiselect component

* Fix style issues

* Add custom renderer for options

* Fix model test

* Update ENTER functionality for multiselect control

* Remove buttons from multiselect UI control

* Updating group messaging UI (#5524)

* Move filter controls up a component level

* Scroll with arrow keys

* Updating mobile layout for multiselect (#5534)

* Fix race condition when backspacing quickly

* Hidden or new GMs show up for regular messages

* Add overriding of number remaining text

* Add UI filtering for team if config setting set

* Add icon to channel switcher and class prop to status icon

* Minor updates per feedback

* Improving group messaging UI (#5563)

* UX changes per feedback

* Update email for group messages

* UI fixes for group messaging (#5587)

* Fix missing localization string

* Add maximum users message when adding members to GM

* Fix input clearing on Android

* Updating group messaging UI (#5603)

* Updating UI for group messaging (#5604)

app/email_batching.go

@@ -244,6 +244,8 @@ func renderBatchedPost(template *utils.HTMLTemplate, post *model.Post, teamName
 		return ""
 	} else if channel := result.Data.(*model.Channel); channel.Type == model.CHANNEL_DIRECT {
 		template.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.direct_message")
+	} else if channel.Type == model.CHANNEL_GROUP {
+		template.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.group_message")
 	} else {
 		template.Props["ChannelName"] = channel.DisplayName
 	}